1 struct sysfs_elem_dir { 2 struct kobject * kobj; 3 }; 4 5 struct sysfs_elem_symlink { 6 struct sysfs_dirent * target_sd; 7 }; 8 9 struct sysfs_elem_attr { 10 struct attribute * attr; 11 }; 12 13 struct sysfs_elem_bin_attr { 14 struct bin_attribute * bin_attr; 15 }; 16 17 /* 18 * As long as s_count reference is held, the sysfs_dirent itself is 19 * accessible. Dereferencing s_elem or any other outer entity 20 * requires s_active reference. 21 */ 22 struct sysfs_dirent { 23 atomic_t s_count; 24 struct rw_semaphore s_active; 25 struct sysfs_dirent * s_parent; 26 struct list_head s_sibling; 27 struct list_head s_children; 28 const char * s_name; 29 30 union { 31 struct sysfs_elem_dir dir; 32 struct sysfs_elem_symlink symlink; 33 struct sysfs_elem_attr attr; 34 struct sysfs_elem_bin_attr bin_attr; 35 } s_elem; 36 37 int s_type; 38 umode_t s_mode; 39 ino_t s_ino; 40 struct dentry * s_dentry; 41 struct iattr * s_iattr; 42 atomic_t s_event; 43 }; 44 45 /* 46 * A sysfs file which deletes another file when written to need to 47 * write lock the s_active of the victim while its s_active is read 48 * locked for the write operation. Tell lockdep that this is okay. 49 */ 50 enum sysfs_s_active_class 51 { 52 SYSFS_S_ACTIVE_NORMAL, /* file r/w access, etc - default */ 53 SYSFS_S_ACTIVE_DEACTIVATE, /* file deactivation */ 54 }; 55 56 extern struct vfsmount * sysfs_mount; 57 extern struct kmem_cache *sysfs_dir_cachep; 58 59 extern void sysfs_delete_inode(struct inode *inode); 60 extern struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent *); 61 extern int sysfs_create(struct sysfs_dirent *sd, struct dentry *dentry, 62 int mode, int (*init)(struct inode *)); 63 64 extern void release_sysfs_dirent(struct sysfs_dirent * sd); 65 extern int sysfs_dirent_exist(struct sysfs_dirent *, const unsigned char *); 66 extern struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, 67 int type); 68 extern void sysfs_attach_dirent(struct sysfs_dirent *sd, 69 struct sysfs_dirent *parent_sd, 70 struct dentry *dentry); 71 72 extern int sysfs_add_file(struct dentry *, const struct attribute *, int); 73 extern int sysfs_hash_and_remove(struct dentry * dir, const char * name); 74 extern struct sysfs_dirent *sysfs_find(struct sysfs_dirent *dir, const char * name); 75 76 extern int sysfs_create_subdir(struct kobject *, const char *, struct dentry **); 77 extern void sysfs_remove_subdir(struct dentry *); 78 79 extern void sysfs_drop_dentry(struct sysfs_dirent *sd, struct dentry *parent); 80 extern int sysfs_setattr(struct dentry *dentry, struct iattr *iattr); 81 82 extern spinlock_t sysfs_lock; 83 extern spinlock_t kobj_sysfs_assoc_lock; 84 extern struct rw_semaphore sysfs_rename_sem; 85 extern struct super_block * sysfs_sb; 86 extern const struct file_operations sysfs_dir_operations; 87 extern const struct file_operations sysfs_file_operations; 88 extern const struct file_operations bin_fops; 89 extern const struct inode_operations sysfs_dir_inode_operations; 90 extern const struct inode_operations sysfs_symlink_inode_operations; 91 92 static inline struct sysfs_dirent * sysfs_get(struct sysfs_dirent * sd) 93 { 94 if (sd) { 95 WARN_ON(!atomic_read(&sd->s_count)); 96 atomic_inc(&sd->s_count); 97 } 98 return sd; 99 } 100 101 static inline void sysfs_put(struct sysfs_dirent * sd) 102 { 103 if (sd && atomic_dec_and_test(&sd->s_count)) 104 release_sysfs_dirent(sd); 105 } 106 107 /** 108 * sysfs_get_active - get an active reference to sysfs_dirent 109 * @sd: sysfs_dirent to get an active reference to 110 * 111 * Get an active reference of @sd. This function is noop if @sd 112 * is NULL. 113 * 114 * RETURNS: 115 * Pointer to @sd on success, NULL on failure. 116 */ 117 static inline struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) 118 { 119 if (sd) { 120 if (unlikely(!down_read_trylock(&sd->s_active))) 121 sd = NULL; 122 } 123 return sd; 124 } 125 126 /** 127 * sysfs_put_active - put an active reference to sysfs_dirent 128 * @sd: sysfs_dirent to put an active reference to 129 * 130 * Put an active reference to @sd. This function is noop if @sd 131 * is NULL. 132 */ 133 static inline void sysfs_put_active(struct sysfs_dirent *sd) 134 { 135 if (sd) 136 up_read(&sd->s_active); 137 } 138 139 /** 140 * sysfs_get_active_two - get active references to sysfs_dirent and parent 141 * @sd: sysfs_dirent of interest 142 * 143 * Get active reference to @sd and its parent. Parent's active 144 * reference is grabbed first. This function is noop if @sd is 145 * NULL. 146 * 147 * RETURNS: 148 * Pointer to @sd on success, NULL on failure. 149 */ 150 static inline struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd) 151 { 152 if (sd) { 153 if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent))) 154 return NULL; 155 if (unlikely(!sysfs_get_active(sd))) { 156 sysfs_put_active(sd->s_parent); 157 return NULL; 158 } 159 } 160 return sd; 161 } 162 163 /** 164 * sysfs_put_active_two - put active references to sysfs_dirent and parent 165 * @sd: sysfs_dirent of interest 166 * 167 * Put active references to @sd and its parent. This function is 168 * noop if @sd is NULL. 169 */ 170 static inline void sysfs_put_active_two(struct sysfs_dirent *sd) 171 { 172 if (sd) { 173 sysfs_put_active(sd); 174 sysfs_put_active(sd->s_parent); 175 } 176 } 177 178 /** 179 * sysfs_deactivate - deactivate sysfs_dirent 180 * @sd: sysfs_dirent to deactivate 181 * 182 * Deny new active references and drain existing ones. s_active 183 * will be unlocked when the sysfs_dirent is released. 184 */ 185 static inline void sysfs_deactivate(struct sysfs_dirent *sd) 186 { 187 down_write_nested(&sd->s_active, SYSFS_S_ACTIVE_DEACTIVATE); 188 189 /* s_active will be unlocked by the thread doing the final put 190 * on @sd. Lie to lockdep. 191 */ 192 rwsem_release(&sd->s_active.dep_map, 1, _RET_IP_); 193 } 194 195 static inline int sysfs_is_shadowed_inode(struct inode *inode) 196 { 197 return S_ISDIR(inode->i_mode) && inode->i_op->follow_link; 198 } 199